Light-sensitive material for the photomechanical preparation of printing plates



United States Patent LIGHT-SENSITIVE MATERIAL FOR THE PHOTO- MECHANICAL PREPARATION OF PRINTH IG PLATES Oskar Siis, Wiesbaden-Biehrich, Germany, assignor, by mesne assignments, to Azoplate Corporation, Murray Hill, N.J., a corporation of New Jersey No Drawing. Filed July 28, 1958, Ser. No. 751,114

Claims priority, application Germany Aug. 3, 1957 26 Claims. (Cl. 9633) This invention relates to novel presensitized printing plates, and to a method for the preparation thereof and, more particularly, to presensitized printing plates the lightsensitive coatings of which comprise a quinone-(1,2)-diazide-sulfonic acid, esterified with a Z-hydroxyaryl-arylimidazole.

It is known to the art to prepare printing plates from flexible, usually foil-type supports, having a light-sensitive coating thereon, which is exposed to light under a master containing the image to be duplicated, and then converted into the actual printing plate by so-called development, to a positive or negative reproduction of the image. The light-sensitive coatings can be prepared with or without colloids, such as synthetic resins and the like.

Of the printing plates containing colloid-free light-sensitive coatings, those prepared from a certain class of diazo compounds are of special practical interest, i.e. those diazo compounds prepared from the sulfonic acid esters of ortho-quinone diazides, particularly those of the benzene or naphthalene series. If the quinone-(1,2)-diazide sulfonic acid esters used to form the light-sensitive coatings contain additional basic groups in the molecule, e.g. a methyl group substituted by a basic radical, or an imidazole ring, the coating, when exposed to light under a positive master, can be developed by means of an acid developer in such a manner that a negative printing image of the master is produced. The ortho-quinone diazide sulfonic acid esters, having basic groups in the molecule, previously used had a tendency to crystallize, which complicated the production of a thin uniform coating on the surface of the support.

In accordance with the present invention, it has been found that presensitized printing plates of excellent quality may be prepared wherein the light-sensitive coating comprises benzoquinone-(l,2) -diazide-sulfonic acids or naphthoquinone-(l,2)-diazide sulfonic acids, esterified with Z-hydroxyaryl-benzimidazoles, or 2-hydroxyary1- naphtho-imidazoles in which the hydrogen atom attached to the nitrogen of the imidazole ring is replaced by another substituent. The esters which may be used in accordance with the present invention are those having the formula '11 N D--SOzO-RC R:

in which D is a quinone-(1,2)-diazide radical, preferably a benzoquinone or naphthoquinone-(1,2)-diazide radical, R and R are substituted or unsubstituted arylene radicals, and R may be alkyl, substituted alkyl, aralkyl, aryl, or a substituted aryl radical.

The presensitized printing plates produced according to the present invention, have coatings of the greatest possible uniformity of composition, and the conversion of which to printing plates consists of operations susceptible of good control. It is unnecessary to use mixtures of light-sensitive diazo compounds, or mixtures of diazo compounds with erystallization-inhibiting substances such as resins, because the diazo compounds corresponding to the general formula given above, have no tendency to form zones of crystallization, and the use of these diazo compounds results in coatings having very good storageability. However, the use of mixtures of several diazo compounds, or of diazo compounds with resins in the formation of light-sensitive coatings, is not precluded.

The diazo compounds employed are insoluble in water, but soluble in organic solvents; they have weakly basic properties which result from the presence of the imidazole ring in the molecule.

In the preparation of the light sensitive coatings, the diazo compounds are applied, in solution in an organic solvent, to a suitable support in any conventional manner, for example by whirl-coating, by direct application or by the immersion process. Solvents having reasonable volatility are preferred, i.e. those having a boiling point in the range of about to C. The support with the solution coated thereon is then dried at temperatures which preferably should not exceed 100 C. It has also been found advantageous to pass a hot air current over the coated surface.

Among the supports which are suitable for use in the preparation of the presensitized printing plates of the invention are foils of paper or metal, preferably aluminum foils, the surface of which may have been roughened mechanically or by chemical treatment or may have been anodically oxidized.

Printing plates are obtained from the presensitized printing plate in accordance with any of the known photomechanical processes, for example a light sensitive aluminum foil is exposed to light under a transparent master, and the image formed is then treated with an acid developer, for example an aqueous solution of a mineral acid or an acid salt. Organic solvents, such as alcohols, or the higher boiling-point hydrocarbons, as well as colloids such as gum arabic, may be added to the acid developers, if desired.

Since the indene carboxylic acids formed on the light exposed parts of the foil (see 0. Siis, Liebigs Annalen der Chemie, vol. 556 (1944), page 64 et seq.) have more weakly basic properties than does the original diazo compound which remains unexposed to light in those areas protected by the covering lines of the master, the acid treatment removes only the latter, while the light decomposition product remains on the support; the light decomposition product is oleophilic, and therefore accepts greasy printing ink. Printing plates are obtained which are negatives of the master, i.e. negative printing plates from positive masters, and vice versa; these can be used in the ordinary printing machines used in duplicating practice. The developed printing plates have great resistance to mechanical wear and are therefore capable of long runs.

The diazo compounds of the invention are novel compositions of matter, and are produced by the reaction of equimolecular quantities of sulfonic acid chlorides of benzoquinone or naphthoquinone-(1,2)-diazides, and 2-hydroxyaryl-benzimidazoles or Z-hydroxyaryl-naphthoimidazoles which are reacted in a suitable organic solvent in the presence of a basic compound, such as sodium carbonate.

In the preparation of the new diazo compounds, the reactants are dissolved in an organic solvent, such as diox-ane, to which it may be desired to add dimethylformarnide. The two solutions are then mixed and an acid-binding agent, for example dilute aqueous sodium carbonate solution, is slowly added to the mixture, while stirring, over a period of two or three hours, the reaction temperature being maintained between 2.0 and 30 C. The quinone-(l,2)-diazide-sulfonic acid esters produced can be purified by recrystallization from organic solvents, or by solution and reprecipitation, for example, by dissolving in dilute hydrochloric :acid and precipitation with sodium bicarbonate solution. The esters are yellow in formulae: 5

Formula 1 0 CH1; II I Formula 2 (3H3 I 1 N sol-0G0 Formula 3 f O SO2O C Formula 4 CH SOzO- c OCH N Formula 5 0 I (3H3 N V SOTO-QC x 0CH N Formula 6 SO20 -C\ Formula 7 Formula 8 Formula 9 Formula 11 Formula 12 Formula 13 O CH;

7 Formula 26 E soy-0 0 C OCH; N

Formula 27 SOz-O-O-O Formula 28 c JHr-cm-N H v 0fl-0- o OOH; N

Formula 29 Formula 30 c\ %n N v SO2-O l Formula 31 ([JHaCHzOH s0T-0 -c CH3 N Formula 32 CHgCHgOH l I ND 8 Formula 33 OCH:

CHaCHzOH Formula 34 OCH:

Formula 35 Is N2 1 0 l Formula 36 N SO2O Formula 37 0 CH3 1 H N T N, CH8 v G SOT-O- Formula 38 Sou-O 9 Formula 39 I SO -O Formula 40 Formula 41 CIJHZCHQCH;

SO2-O Formula 42 Formula 43 Formula 44 Cl 2H5 N 1 3 Formula 45 (III) CH3 N 2N2 0 CH3 SOr-O Formula 46 Formula 47 CHzCHzOH S'WO Formula 48 0 CH: H 1 N2 /N I Or-O N 50 Formula 49 0 CH; ll I N2 Formula 50 SIC: (111 O /N SOPO-GO hydroxyaryl-benzimidazoles naphthoimidazoles used in the esterification reaction are prepared in the manner described in Liebigs Annalen der 12 TABLE 11 and hydroxyaryl- 5 Chemie, vol. 575 (1952), pages 162-l69, by the reaction of o-diamines of the benzene or naphthalene series,

1 1'. Formula 51 o 0 II II The N2 Na so,o o-03 ing agents. (,1 N N 0 10 N I CH: (LH: 15

Formula 52 o o I ll do 0 o-o s T- CH3 CH3 2 G CN g NC- In Table I below, are listed the reaction components 30 from which the compounds having the formulae given above can be prepared, in accordance with the previously described procedure:

TABLE I with aromatic hydroxyaldehydes in alcoholic solution, nitrobenzenes being used where necessary as dehydrogenat- -In the many cases where atmospheric oxygen is suflicient for ring closure with dehydrogenation, the addition of these dehydrogenating agents is unnecessary.

Quinone-(l,2)-diazide-sulionic acid chloride 2-hydroxyaryl-benzimidazole or 2- hydroxyaryl-naphthoimidazole from Table II Melting point with decomposition, O.

Naphthoquinone- (1,2)-diazide- (2)-4-sulphochloride, 6 parts by weight N aphthoquinone-(1,2)-diazide-(2)-4-sulphochloride, 1.5 parts by wieght- Naphthoquinone-(1,2)-diazide-(2)-5sulphoehloride, 0.8 part by weight". Naphth0quin0ne-(L2)-diazide-(2)4-sulphoehloride, 3 parts by weight.-- Naphthoquinone-(1,2)-d iazide-(2)-5sulphochloride, 1.5 parts by weight- Naphthoquinone- (1,2)-diazide-(2)4-sulphochloride, 1.5 parts by weight" N aplthoquinone-(1,2)-d.iazide-(2)-4-sulphoehloride, 3 parts by Weight I4.5 parts by weight II-Ll parts by weigh 0.6 part by weight III-2.54 parts by weigh III-1.27 parts by weight IV1.2 parts by Weight V2.5 parts by weight VI2.7 parts by weight- Napthoquinone-(1,2)-diazide-(2)-5-sulphochloride, 3 parts by Weight- N aplthoquinone-(1,2)-diazide- (2)-4-sulphochloride, 3 parts by weight o N aphthoquinone-(1,2)-d.iazide-(2)-5-sulphochloride, 3 parts by wieght.- Naphthoquinone- (1,2)-djazide-(2)-4-sulphochloride, 3 parts by weight" Naphthoquinone-(1,2)-d azide-(2)-5-sulphoch1oride, 0.8 part by weight Naphthoquinone-(1,2)-d.iazide-(2)-4-sulphoehloride, 1.9 parts by Weight- N aphthoquinone- (1,2)-diazide-(2)-4-sulphoehloride, 3 N aphthoquinone-(1,2) -diazide-(2) -5-sulphochlon'de, 3 parts by weight Naphthoquinone-(1,2)-diazide-(2)-5-sulphochloride, 3 parts by weight N aphthoqninone-(1,2)-diazide-(2)-4'sulphochl0ride, 3 parts by weight N aphthoquinone-(l,2)-diazide-(2)-5-sulphochloride, 3 parts by wei ht do VII-25 parts by weight VIII-2.5 parts by Weight IX2.7 parts by weight X-2.5 parts by weight. I0.5 part by weight XIl.65 parts by weigh XII -3 parts by weight- XVII2.23 parts by Weight XIX-2.7 parts by weight xx r r az parts by Weight Naphthoquinone-(1,2)-diazide-(2)-4-sulphocbloride, 3 parts by weight Naphthoquinone-(1,2)-diazide-(2)-5-sulphochloride, 3 parts by wei ht XXlLII3.2 parts by Weight Naphthoquinone-(1,2)-diazide-(2)-4-sulphochloride, 3 parts by Weight; Naphthoquinone-(1,2)-diazide-(2)-5-sulphochloride, 3 parts by weiuht O XXIV-3 parts by Weight Napglthoquinone-(1,2)diazide-(2)-4-sulphochloride, 3 parts by Weight fiaphthoquinone-(1,2)-diazirle-(2)-4-sulphocbloride, 2 parts by weight Naphthoquinone-(1,2)-diazide-(2)-4-sn1phochloride, 3 parts by weight dn Nap thoquinone-(lfl)-diazide-(2)-5-s11lphochloride, 3 parts by weight Napbthoquinone- (1,2) -diazide- (2) -4-sulphochloride, 3 parts by weight 0 Naphthoquinone-(l,2)-diazide-(2)-4-sulphochloride, 1.65 parts by Weight Naphthoquinone-(1,2)-diazide-(2)-4-sulphoehloride, 3 parts by weight Benz0quinone-(1,2)-diazide-(2)-4-sulphochlorit1e, 2.3 parts by weiubt XXX-2.25 parts by weight XXXI2.7 parts by weight. XXXII2.5 parts by Weight XXXIII2.5 parts by weight- XXXIV2.6 parts by Weight XXXV-1.45 parts by weight- XXdXVI2.7 parts by weight fl Naphthoquinone-(1,2)-diazi le-(2)-4-sulphochloride, 3 parts by Weight Naphthoquinone-(1,2)-diazide-(2)-4-sulph0chloride, 1.5 parts by weight Naphthoquinone-(1,2)-diazide-(2)-4-su lphochloride, 3 parts by weight XXXVII1.2 parts by weight XXXVIII-LO5 parts by weight" XXXLX2.3 parts by Weight 1 Not sharp.

. 1 Not sharp c.

Compounds I to XXI given in Table II below, are obtained in this manner, for example:

The image obtained was developed by swabbing it with TABLE II 2-hydroxyaryl-benziruidazoles and 2-hydroxy- Diamines Aromatic hydroxy- Addition Melting aryl-naphthimidazoles aldehyde p oiit,

1-methyl-2-(2-hydroxyphenyl)-benzimidazole N-methyl-o-phenylene-diamine 2-l1i1yd1roxy-benzalde- 1, g-di-nitro- 164-165 y e enzene. 1-methyl-2-(4-hydroxyphenyl)-benzimidazole do 4-l111yd1roxy-benzalde- 233-285 y e. 1-methyl-2-(4-hydroxy-3-methoXy-phenyl) .-do 4-hydroxy-3-methoxy- 203-205 benzimidazole. benzaldehyde. 1-ethyl-2-(4-hydroxyphenyl)-benz1rn1dazole; N-ethyl-o-phenylene diamine 4-l111y((l1roxy-benza1de- 242-245 y e. l-propyl-2-(4-hydroXy'phenyl)-beIlZiInid2Z01e N-propylo-phenylene d1amine do 239-240 1-butyl-2-(4-hydroxyphenyl)-benzimidazole N-butylo-phenylene-diamine .do 168-170 l-rnetgyl-2l-(4-hydroiryphenyl)-6-methoxy-benz- 4-amino-5-rnethylaminoole 263-266 inn azo e. l-ethyl12-(4 hydroxyphenyl)-6-methyl-benzirn- 4-amino-5-ethy1-amino toluene--- do 287-289 idazo e. 1-methyl-2-(4-hydroxyphenyl)-5-nitro-benzim- 1-nitro-3-amin0-4-methyl-amtnod 112-113 idazele. benzene l-methyl 2-(3-hydioxy-4-metho2q7-phenyl)-benz N-methyl-o-phenylene-diamine. 3-hydroxy-4-rnethoxy- Nltrobenzene 194-195 imidazole. benzaldehyde. l-B-hydroxy-ethyl-2-(4-hydroxyphenyl)-benzim- N-B-hydroxyethyl-o-phenylene- 4-hydroxy-benzalde- .5. 196-198 idazole. diamine. hyde. 1-b9nzyl-2-(4-hydroxyphenyl)-benzimidazole. N-benzyl-o-phenylene-diamine. do Nitrobenzene 232-234 1-phenyl-2-(4-hydroxyphenyl)-benzimidazole N-phenyl-o-phenylene-diamine.. do do 280-281 1-methy1-2-(4-hydroxy-naphthyl) be11zimidazole N-methyl-o-phenylene-diamiue 4-l11lyd1roxy-naphthalde- 310-312 y e. 1-methy1-2-(2-hydroxynaphthyl)-benzimidazole do 2l111ydiroxy-naphthalde- Nitrobenzene 288-290 e. Bis-[1-methyl-2-(4-l1ydroxyphenyl) benzimida- 3,3-di-amino-4,4-bis-methyl- 4-nydroXy-benzalde 322-326 zolyl-()]-methane. aminodinhenyl-methane. hyde (2 mols). Bis-[2-(4-hydroxyphenyl)-benzimidazolyl- N,N-bis-(2-aminophenyl)- 1o Nitro- 403-404 (1)]-a, B-ethane. ethylene diamine. benzene. l-fi-piperidinoethyl-Q- (4-hydroxy-3-methoxy- N-(B-piperidinoethyD-o- 4-hydroxy-3-inethoiry- 'rn-Dinitro- 165-167 phenyl)-benzimidazole. phenylene diamine. benzaldehyde. benzene. 1-(4-dimethyl-amino-phenyl)-2-(4-hydr0xy3- 2-amino-4-dirnethyl-amin0- d0 Nitro- 225-226 methoxy-phenyl)-benzimidazole. diphenyl-amine. benzene. 1-methy1-2-(3'-hydroxyphenyl)-benzimidazole N-Inethyl-o-pheny1enediam.tne 3-llilydlroxy-benzaldemgDinitro- 187 y e. enzene. 1-methyl-2-(2-hydroryphenyl)-[naphtho-1,2, N-methyl-naphthylene-diamine 2-hydroxy-benzalded0 157-158 4,5-imidazole]. hyde. 1 -B-hyd.roXy-ethyl-2- (4 -hydroxy -3 -methoxy- N-B-hydroxy-ethyl-o-phenylene- 4-hydroxy-3-methoxy- 1,3-dinitro- 250-252 phenyD-benzimidazole. diamine. benzaldehyde. benzene. l-fi-hydroxy-ethyl-2-(3-hydroxy-4-meth0xy- -d0 3-hydroxy4-methoxydo 219-220 phenyl)-benzin1idazo1e. benzaldehyde. 1-benzyl-2-(2'-hydroxyphenyl)-benzimidazole N-benzyl-o-phenylene-diamine 2-llilyrroxy-benzaldedo 177-178 y e. l-methy1-2-(2-hydroxyphenyl)-6-methyl-be11z- 4-amino-5-methyl-ami'nodo do 144 imtdazole. toluene. l-methyl-2-(2-hydr0xypheny1)-5-methyl-henz- 3-amino-4-methyl-amino- -do do 184-185 imidazole. toluene. 1-pl:enyl-2-(2'-hydroxypheny1)-benzimidazole. N-phenyl-o-phenylene-diamine 106-107 1-ethyl-2-(2'-hydroxyphenyl)-benzimidazole N-ethyl-o-phenylene-diamine 129 1-propyl-2-(2-hydroxyphenyl)-benzimidazole N-propylo-phenylene-diamine. do.-. 130-131 l-methyl-2-(3-hydroxy'phenyl)-benzimidazole N-methyl-o-phenylenediamine. 3-lI11yc(l1roxy-benzalde- 187 v y XXXI l-methyl-2-(2-hydroxyphenyl)-5-nitro-benzim- N-nitro-3-amino4-methylan1ino- 2-hydroxy-benzalde- 1,3-dinitro- 182-185 idazole. benzene. hyde. benzene. XXXII l-eghyl-f-(2-hydroxyphenyl)-6-methyl-benzim- 4-an1ino-5-ethylamino-toluene do do 133-136 i azo e. XXXI1I 1-metgyl-2-(2-hydroxyphenyl)-6-methoxy-benz- 4-amino-5-methylamino-anisola do do 153-154 imi azo e. XXXIV 1-methyl-2-(2'-hydroxyphenyl)-6-chlor0-benz- 4-amino-5-methylamino-1- do do 139-141 imidazole. V chloro-benzene. V XXXV l-fl-hydroxy-ethyl-Z-(2'-l1ydroxyphenyl)-benz- N-B-hydroxy-ethyl-o-phenylene do do 157-158 imidazole. diamine. XXXVI i-methytll-2-(aihydroxyphenyl)-[naphth0-2,3, N-n1eithyl-naphthylene-diamine do do 155-156 -11111 azoe a XXXVII. 1-methyl-2-(2,4-di-hydroxyphenyl)-benzimida- N-methyl-o-phenylene-di-amine 2,4fldiihydroxy-benzaldedo 122-138 7 z e. y e. XXXVIII-.. Bis-[1-methyl-2-(2-hyd.r0xypheny1)l-naphtho-l, 1,8-diamino-2,7-di-(methyl- 2-hydroxy-benzalde- 330-335 2,7,8-imidazole. amino)-naphthalene. by e. XXXIX. Bis-[l-methyl- -(2-hydroxyphenyl)-benzimida- 3,3-diamino-4,4-bismethyl- 2-hydroxy-benzalde- 1,3-dinitro- 264 zolyl-(5)]-methane. ammo-diphenyl-methane. hyde (2 mols). benzene.

1 Hydrochloride. 2 Not sharp.

The invention will be further illustrated by the following specific examples:

An aluminum foil, brushed on one side, was whirlcoated on the brushed side with a solution of 1 part by weight of the diazo compound corresponding to Formula 1 above, in 100 parts by volume of glycolmonomethylether. The coating was dried in a hot air current and the foil was then further dried for a period of two minutes at a temperature of 100 C., to insure complete removal of the solvent. The dried coating was then exposed to light under a film negative, i.e. to an 18 amp. arc lamp, at a distance of cm. for a period of about one minute.

Example 1 then be inked up immediately with greasy ink, either by hand or using a conventional printing apparatus, and used for printin From a negative master, a positive printing be made.

phosphoric acid listed.

developing solution.

plate is obtained, from which several thousand prints can It may be desirable in some cases to add a thickening agent, such as gum arabic or dextrin, to the Equally good results were obtained using, instead of the sulphonic acid ester corresponding to Formula 1 above, the diazo compound corresponding to those listed in Table I. Slight changes in coating procedure and developing solutions will be obvious to those skilled in the art, but in the following table certain diiferences are i l :3 TABLE III Formula N o. to which Solvent for the compound diazo compound Developer solution corresponds 3 Glycolmonomethphosphoric acid solution.

ylegher pyridine 4 As in Example 1.- Do. 5--. do Do. 6--.. 51-10% phosphoric acid solution. 8 phosphoric acid solution. 9 5% phosphoric acid solution. 10 10% phosphoric acid solution. 12 do 80% ethylalcohol solution with 5% of phosphoric acid. 13 Glycolmonometh- As in Example 1.

ylether dimethylformamide (1:1). 15 As in Example 1 l5% phosphoric acid solution. 16 do 60-80% ethylalcohol solution with 2.5%

of phosphoric acid.

10% phosphoric acid solution.

50% ethylalcohol solution with 2.5% of phosphoric acid.

5% phosphoric acid solution.

40% propylalcohol solution with 2.5%

of phosphoric acid.

5% phosphoric acid solution.

80% ethylalcohol solution with 5% of phosphoric acid.

phosphoric acid. 20% monosodium phosphate solution. 5% sulphuric acid solution. As in Example 1.

Example 2 A paper foil prepared in accordance with the disclosure of US. Patent No. 2,534,588, was coated on the coating side with a 1.5 percent by weight solution of the compound of Formula 14 above, in glycolmonomethyl- 40% ethylalcohol solution with 2.5% of t 1% the image, a 10 percent phosphoric acid solution was used. When the developed coating was inked up with greasy ink, a positive printing plate was obtained, as the result of the use of a negative master.

Example 6 ing plate was obtained from a negative master, which ether, and was dried for about 2 minutes at a temperature of about 90 to 100 C. The light-sensitive foil was then exposed to light beneath a negative film master, and developed with a 0.5 percent by weight phosphoric acid solution. When the developed coating was inked up with greasy ink, a positive printing plate was obtained.

Example 3 Following the general procedure of Example 1 above, an anodically oxidized aluminum foil was coated with a solution of one part by weight of the diazo compound of Formula 15 in 100 parts by'volume of glycolmonomethylether, dried, and exposed to light under a master. The plate was developed by swabbing with a 15 percent by weight phosphoric acid solution. A positive printing plate was obtained trom the negative master.

Example 4 Following the general procedure of Example 1 above, a 1 percent by weight solution of the compound of Formula 16 in glycolmonomethylether was applied to an aluminum foil, mechanically brushed on one side and then dried. The light-sensitive foil was exposed to light under a transparent master, and developed by treatment with a 60-80 percent solution of ethylalcohol, containing 2.5 percent by weight of phosphoric acid. A positive pn'nting plate was obtained from the negative master.

Equally good results were achieved using the compounds corresponding to Formulae 2 to 23 above. For the development of the image to a completed printing plate, slight variations in the developer solutions are necessary for the individual diazo compounds; note the data given in Example 1 above.

Example 5 Following the general procedure of Example 1 above, a light-sensitive aluminum foil was coated with the diazo compound of Formula 24, and made into a printing plate in the conventional fashion. 'For the development of could be used for printing after being inked up with greasy ink.

Example 7 An aluminum foil roughened on one side by brushing, was coated with a 1.5 percent solution of the compound of Formula 26 in glycolmonomethylether, and then dried. The foil was then exposed to light under a transparent master, developed with a 5 percent phosphoric acid solution, and the image was then inked up with greasy ink. A positive printing plate was obtained from the negative master.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. A compound having the formula in which D is a quinone-(l,2)-diazide radical, R and R are arylene groups, and R is selected from the group consisting of alkyl, and aralkyl and aryl groups.

2. A compound having the formula in which D is a quinone-(l,2)-diazide radical, R and R are arylene groups, and R is an alkyl group.

3. A compound having the formula in which D is a quinone-(1,2)-diazide radical, R is an arylene group, R is an aralkyl group, and R is an arylene group.

4. A compound having the formula in which D is a quinone-(l,2)- diazide radical, R and R are arylene groups, and R is an aryl group.

5. A presensitized printing plate comprising a base material having a coating thereon comprising a compound having the formula in which D is a quinone-(1,2)-diazide radical, R and R are arylene groups, and R is selected from the group consisting of alkyl, aralkyl and aryl groups.

in which D is a quinone(1,2)- diazide radical, R and R are arylene groups, and R is an alkyl group.

7. A presensitized printing plate comprising a base material having a coating thereon comprising a compound having the formula in which D is a quinone(1,2)-diazide radical, R is an arylene group, R is an aralkyl group, and R is an arylene group.

8. A presensitized printing plate comprising a base material having a coating thereon comprising a compound having the formula 1 N n-so -o-a-c 11 in which D is a quinone-(l,2)-diazide radical, R and R are arylene groups, and R is an aryl group.

9. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-(1,2)-diazide radical, R and R are arylene groups, and R is selected from the group consisting of alkyl, aralkyl and aryl groups, and treating the light-exposed coating with an acidic developer.

10. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-(1,2)-diazide radical, R and R are arylene groups, and R is an alkyl group, and treating the light-exposed coating with an acidic developer.

11. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula f1 N n-so -o-a-c 123.

in which D is a quinone-(1,2) -diazide radical, R is an arylene group, R is an aralkyl group, and R is an arylene group, and treating the light-exposed coating with an acidic developer.

12. A method of developing a presensitized printing plate which comprises exposing to light under a master a 18 base material having a coating thereon comprising a compound having the formula in which D is a quinone-(1,2)diazide radical, R and R are arylene groups, and R is an aryl group, and treating the light-exposed coating with an acidic developer.

13. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-(1,2)-diazide radical, R and R are arylene groups, and R is selected from the group consisting of alkyl, aralkyl and aryl groups, and treating the light-exposed coating with dilute phosphoric acid solution.

14. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-'(1,2)-diazide radical, R and R are arylene groups, and R is an alkyl group, and treating the light-exposed coating with dilute phosphoric acid solution.

15. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-(l,2)-diazide radical, R is an arylene group, R is an aralkyl group, and R is an arylene group, and treating the light-exposed coating with dilute phosphoric acid solution.

16. A method of developing a presensitized printing plate which comprises exposing to light under a master a base material having a coating thereon comprising a compound having the formula in which D is a quinone-'( l,2)-diazide radical, R and R are arylene groups, and R is an aryl group, and treating the light-exposed coating with dilute phosphoric acid solution.

17. A compound having the formula .18. A compound having the formula 1 9.' A compound having the formula 20 -A compound having the formula SOr-O 21. A compound having the formula I OCH 22. A compound having the formula 23. A compound having the formula- Sm-O-O-C 24. A compound having the formula 2 5. A compound having the formula 26. A compound having the-formula Referencee Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Ierchel et al.: Liebigs Annalan der Chemie, v61. 57s,

1952, pages 162-173, v 

5. A PRESENSITIZED PRINTING PLATE COMPRISING A BASE MATERIAL HAVING A COATING THEREON COMPRISING A COMPOUND HAVING THE FORMULA 